A conventional navigation apparatus divides map data into multiple segment data, which correspond to individual segment map areas, and updates each of the multiple segment data when needed (see Patent document 1).
A map edition display apparatus edits the map data used in the above navigation apparatus and manages update history. The map edition display apparatus is capable of discernibly displaying updated portion on a map (see Patent document 2).
Thus, the update history of map data can be managed and updated portions can be discernibly displayed in the combination of the above navigation apparatus and map edition display apparatus. This allows a user to easily discern a new road or modified road portion.
However, as the map data are repeatedly updated, earlier updated portion and later updated portion become indiscernible from each other on the display.
Patent document 1: JP-A-2006-18086
Patent document 2: JP-A-2002-318532